Meiotic maturation induces animal-vegetal asymmetric distribution of aPKC and ASIP/PAR-3 in Xenopus oocytes

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5021-5031 ◽  
Author(s):  
M. Nakaya ◽  
A. Fukui ◽  
Y. Izumi ◽  
K. Akimoto ◽  
M. Asashima ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Polarity ◽  
Contact Region ◽  
Cell Polarization ◽  
Meiotic Maturation ◽  
Cell Contact ◽  
Asymmetric Distribution ◽  
Germinal Vesicle Breakdown ◽  
General Role ◽  
Immature Oocytes

The asymmetric distribution of cellular components is an important clue for understanding cell fate decision during embryonic patterning and cell functioning after differentiation. In C. elegans embryos, PAR-3 and aPKC form a complex that colocalizes to the anterior periphery of the one-cell embryo, and are indispensable for anterior-posterior polarity that is formed prior to asymmetric cell division. In mammals, ASIP (PAR-3 homologue) and aPKCgamma form a complex and colocalize to the epithelial tight junctions, which play critical roles in epithelial cell polarity. Although the mechanism by which PAR-3/ASIP and aPKC regulate cell polarization remains to be clarified, evolutionary conservation of the PAR-3/ASIP-aPKC complex suggests their general role in cell polarity organization. Here, we show the presence of the protein complex in Xenopus laevis. In epithelial cells, XASIP and XaPKC colocalize to the cell-cell contact region. To our surprise, they also colocalize to the animal hemisphere of mature oocytes, whereas they localize uniformly in immature oocytes. Moreover, hormonal stimulation of immature oocytes results in a change in the distribution of XaPKC 2–3 hours after the completion of germinal vesicle breakdown, which requires the kinase activity of aPKC. These results suggest that meiotic maturation induces the animal-vegetal asymmetry of aPKC.

scholarly journals Epigenetic Modification Affecting Expression of Cell Polarity and Cell Fate Genes to Regulate Lineage Specification in the Early Mouse Embryo

2010 ◽  
Vol 21 (15) ◽  
pp. 2649-2660 ◽  
Author(s):  
David-Emlyn Parfitt ◽  
Magdalena Zernicka-Goetz
Keyword(s):  
Cell Fate ◽  
Cell Polarity ◽  
Mouse Embryo ◽  
Inner Cell Mass ◽  
Epigenetic Modification ◽  
Cell Mass ◽  
Time Lapse ◽  
Cell Polarization ◽  
Asymmetric Divisions

Formation of inner and outer cells of the mouse embryo distinguishes pluripotent inner cell mass (ICM) from differentiating trophectoderm (TE). Carm1, which methylates histone H3R17 and R26, directs cells to ICM rather that TE. To understand the mechanism by which this epigenetic modification directs cell fate, we generated embryos with in vivo–labeled cells of different Carm1 levels, using time-lapse imaging to reveal dynamics of their behavior, and related this to cell polarization. This shows that Carm1 affects cell fate by promoting asymmetric divisions, that direct one daughter cell inside, and cell engulfment, where neighboring cells with lower Carm1 levels compete for outside positions. This is associated with changes to the expression pattern and spatial distribution of cell polarity proteins: Cells with higher Carm1 levels show reduced expression and apical localization of Par3 and a dramatic increase in expression of PKCII, antagonist of the apical protein aPKC. Expression and basolateral localization of the mouse Par1 homologue, EMK1, increases concomitantly. Increased Carm1 also reduces Cdx2 expression, a transcription factor key for TE differentiation. These results demonstrate how the extent of a specific epigenetic modification could affect expression of cell polarity and fate-determining genes to ensure lineage allocation in the mouse embryo.

scholarly journals Getting to know your neighbor: Cell polarization in early embryos

2014 ◽  
Vol 206 (7) ◽  
pp. 823-832 ◽  
Author(s):  
Jeremy Nance
Keyword(s):  
Cell Fate ◽  
Cell Polarization ◽  
Cell Contact ◽  
Cell Fates ◽  
Par Proteins ◽  
Morphogenetic Movements ◽  
Cell Fate Decisions ◽  
Contact Patterns ◽  
Early Embryos ◽  
Contact Free

Polarization of early embryos along cell contact patterns—referred to in this paper as radial polarization—provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. Although polarity can be established through distinct upstream mechanisms in Caenorhabditis elegans, Xenopus laevis, and mouse embryos, in each species, it results in the restriction of PAR polarity proteins to contact-free surfaces of blastomeres. In turn, PAR proteins influence cell fates by affecting signaling pathways, such as Hippo and Wnt, and regulate morphogenetic movements by directing cytoskeletal asymmetries.

65 OVULATION OF IMMATURE OOCYTES WITH HIGH COMPETENCE RATES

2017 ◽  
Vol 29 (1) ◽  
pp. 140
Author(s):  
A. M. Taiyeb ◽  
S. A. Muhsen-Alanssari ◽  
M. E. Kjelland ◽  
S. M. Taiyeb ◽  
A. I. Haji ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Developmental Competence ◽  
Meiotic Maturation ◽  
Control Group ◽  
Cortical Granule ◽  
Germinal Vesicle Breakdown ◽  
Immature Oocytes ◽  
Antral Follicles ◽  
Significant Difference ◽  
High Competence

Collection of immature oocytes from antral follicles in superovulated mice is a widely established technique for retrieval of germinal vesicle (GV) and metaphase I (MI) oocytes. Investigators use their experience to select antral follicles under a microscope before puncturing the follicles. This is sometimes followed by screening of oocytes based on morphology and diameter, and usually mouse oocytes of small diameters or abnormal morphologies are excluded. Shortcomings with the current technique may include varied oocyte yields and collection of oocytes from primary and secondary follicles. Moreover, such immature oocytes were observed to have different chromatin configurations, cortical granule distributions, spindle-chromosome organizations, fertilization rates, and diameters. This study was designed to investigate the potential of ovulated immature oocytes, resultant from superovulated mice treated with an FDA approved phosphodiesterase 3A inhibitor named cilostazol (CLZ), to substitute for ovarian immature oocytes collected from antral follicles of superovulated mice. Swiss Webster mice were superovulated and gavaged with 7.5 mg of CLZ once, at the same time as hCG injection, or twice, at the same time as hCG plus 6 h post-hCG injection, to result in ovulation of MI or GV oocytes, respectively. Control ovarian GV or MI oocytes were collected from ovarian antral follicles of superovulated mice not treated with CLZ. Ten mice were used in each treatment or control group. Single or multiple administrations of CLZ resulted in mice ovulating 85.8 ± 3.9% MI oocytes or 95.2 ± 3% GV oocytes (mean ± SEM), respectively. Treated GV oocytes had significantly higher rates of advanced chromatin configuration and cortical granule distribution than did control GV oocytes. Treated GV oocytes had lower cAMP levels and higher rates of meiotic maturation, IVF, and blastocyst formation than did control GV oocytes (P < 0.0001). Treated MI oocytes had significantly higher rates of normal spindle and chromosomes aligned at the metaphase plates and offspring than did control MI oocytes. Control or treated GV oocytes were found to have greater diameters than did control or treated MI oocytes, respectively (P < 0.007), indicating that initiation of meiotic maturation is associated with reduction in oocyte diameters and utilisation of cytoplasm proteins and cofactors. Moreover, control GV oocytes were found to have greater diameters than did treated GV oocytes (P = 0.007). This may refer to the readiness of treated GV oocytes to undergo germinal vesicle breakdown and transition into the MI stage, especially treated GV oocytes had high rates of meiotic development in comparison to control GV oocytes. Diameters of GV nuclei in treated GV oocytes were smaller than those in control GV oocytes (P = 0.006), which may also indicate a germinal vesicle that had started to undergo germinal vesicle breakdown. A similar significant difference was also noted with control and treated MI oocytes. In summary, we present a novel method for retrieval of immature oocytes at different stages of meiotic maturation. Treated ovulated immature oocytes had more uniform diameters and high developmental competence than did ovarian immature oocytes. Treated ovulated immature oocytes may substitute for ovarian immature oocytes and become an additional research resource.

scholarly journals The role of nonmuscle myosin 2A and 2B in the regulation of mesenchymal cell contact guidance

2019 ◽  
Vol 30 (16) ◽  
pp. 1961-1973
Author(s):  
Alexander S. Zhovmer ◽  
Erdem D. Tabdanov ◽  
Houxun Miao ◽  
Han Wen ◽  
Jinqiu Chen ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Mesenchymal Cell ◽  
Cell Polarization ◽  
Contact Guidance ◽  
Cell Contact ◽  
Nonmuscle Myosin ◽  
Geometrical Features ◽  
Relationship Of ◽  
The Relationship

Contact guidance refers to the ability of cells to sense the geometrical features of the microenvironment and respond by changing their shape and adopting the appropriate orientation. Inhibition and ablation of nonmuscle myosin 2 (NM2) paralogues have demonstrated their importance for contact guidance. However, the specific roles of the NM2 paralogues have not been systematically studied. In this work we use micropatterned substrates to examine the roles of NM2A and NM2B and to elucidate the relationship of the microenvironment, actomyosin, and microtubules in contact guidance. We show that contact guidance is preserved following loss of NM2B and that expression of NM2A alone is sufficient to establish an appropriate orientation of the cells. Loss of NM2B and overexpression of NM2A result in a prominent cell polarization that is found to be linked to the increased alignment of microtubules with the actomyosin scaffold. Suppression of actomyosin with blebbistatin reduces cell polarity on a flat surface, but not on a surface with contact guidance cues. This indicates that the lost microtubule–actomyosin interactions are compensated for by microtubule–microenvironment interactions, which are sufficient to establish cell polarity through contact guidance.

Triphenyltin chloride induces spindle microtubule depolymerisation and inhibits meiotic maturation in mouse oocytes

2014 ◽  
Vol 26 (8) ◽  
pp. 1084 ◽  
Author(s):  
Yu-Ting Shen ◽  
Yue-Qiang Song ◽  
Xiao-Qin He ◽  
Fei Zhang ◽  
Xin Huang ◽  
...  
Keyword(s):  
Polar Body ◽  
Meiotic Maturation ◽  
Dependent Manner ◽  
Germinal Vesicle Breakdown ◽  
Mouse Oocytes ◽  
First Polar Body ◽  
Triphenyltin Chloride ◽  
Dose Dependent

Meiosis produces haploid gametes for sexual reproduction. Triphenyltin chloride (TPTCL) is a highly bioaccumulated and toxic environmental oestrogen; however, its effect on oocyte meiosis remains unknown. We examined the effect of TPTCL on mouse oocyte meiotic maturation in vitro and in vivo. In vitro, TPTCL inhibited germinal vesicle breakdown (GVBD) and first polar body extrusion (PBE) in a dose-dependent manner. The spindle microtubules completely disassembled and the chromosomes condensed after oocytes were exposed to 5 or 10 μg mL–1 TPTCL. γ-Tubulin protein was abnormally localised near chromosomes rather than on the spindle poles. In vivo, mice received TPTCL by oral gavage for 10 days. The general condition of the mice deteriorated and the ovary coefficient was reduced (P < 0.05). The number of secondary and mature ovarian follicles was significantly reduced by 10 mg kg–1 TPTCL (P < 0.05). GVBD decreased in a non-significant, dose-dependent manner (P > 0.05). PBE was inhibited with 10 mg kg–1 TPTCL (P < 0.05). The spindles of in vitro and in vivo metaphase II oocytes were disassembled with 10 mg kg–1 TPTCL. These results suggest that TPTCL seriously affects meiotic maturation by disturbing cell-cycle progression, disturbing the microtubule cytoskeleton and inhibiting follicle development in mouse oocytes.

Cell polarity and tissue patterning in plants

Development ◽  
1991 ◽  
Vol 113 (Supplement_1) ◽  
pp. 83-93 ◽  
Author(s):  
Tsvi Sachs
Keyword(s):  
Cell Polarity ◽  
Cell Shape ◽  
Auxin Transport ◽  
Developmental Stages ◽  
Important Determinant ◽  
Genetic System ◽  
Cell Patterning ◽  
Cell Polarization ◽  
Sources And Sinks ◽  
Tissue Patterning

Cell polarization is the specialization of developmental events along one orientation or one direction. Such polarization must be an early, essential stage of tissue patterning. The specification of orientation could not occur only at the level of the genetic system and it must express a coordination of events in many cells. There is a positive feedback relation between cell polarization and the transport of the known hormone auxin: polarity determines oriented auxin transport while transport itself induces both new and continued polarization. Since cell polarization increases gradually, this feedback leads to the canalization of transport – and of the associated cell differentiation – along defined strands of specialized cells. Recent work has shown that the same canalized flow can also be an important determinant of cell shape. In primordial, embryonic regions cell growth is oriented along the flow of auxin from the shoot towards the root. In later developmental stages the cells respond to the same flow by growing in girth, presumably adjusting the capacity of the tissues to the flow of signals. Finally, disrupted flow near wounds results in the development of relatively unorganized callus. Continued callus development appears to require the participation of the cells, as sources and sinks of auxin and other signals. The overall picture to emerge suggests that cell patterning can result from competition between cells acting as preferred channels, sources and sinks for developmental signals.

scholarly journals SyNPL: Synthetic Notch pluripotent cell lines to monitor and manipulate cell interactions in vitro and in vivo

2021 ◽  
Author(s):  
Mattias Malaguti ◽  
Rosa Portero Migueles ◽  
Jennifer Annoh ◽  
Daina Sadurska ◽  
Guillaume Blin ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Lines ◽  
Modular Design ◽  
Cell Interactions ◽  
Cell Populations ◽  
Cell Contact ◽  
Pluripotent Cells ◽  
Cell Fate Decisions ◽  
Cell Cell

ABSTRACTCell-cell interactions govern differentiation and cell competition in pluripotent cells during early development, but the investigation of such processes is hindered by a lack of efficient analysis tools. Here we introduce SyNPL: clonal pluripotent stem cell lines which employ optimised Synthetic Notch (SynNotch) technology to report cell-cell interactions between engineered “sender” and “receiver” cells in cultured pluripotent cells and chimaeric mouse embryos. A modular design makes it straightforward to adapt the system for programming differentiation decisions non-cell-autonomously in receiver cells in response to direct contact with sender cells. We demonstrate the utility of this system by enforcing neuronal differentiation at the boundary between two cell populations. In summary, we provide a new tool which could be used to identify cell interactions and to profile changes in gene or protein expression that result from direct cell-cell contact with defined cell populations in culture and in early embryos, and which can be adapted to generate synthetic patterning of cell fate decisions.

Control of photoreceptor cell morphology, planar polarity and epithelial integrity during Drosophila eye development

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2247-2258 ◽  
Author(s):  
Amanda T. Pickup ◽  
Michele L. Lamka ◽  
Qi Sun ◽  
Man Lun R. Yip ◽  
Howard D. Lipshitz
Keyword(s):  
Cell Fate ◽  
Cell Morphology ◽  
Photoreceptor Cell ◽  
Zinc Finger Protein ◽  
Photoreceptor Cells ◽  
Planar Polarity ◽  
Tracheal System ◽  
General Role ◽  
Epithelial Integrity ◽  
Jnk Signaling

We report that the hindsight (hnt) gene, which encodes a nuclear zinc-finger protein, regulates cell morphology, cell fate specification, planar cell polarity and epithelial integrity during Drosophila retinal development. In the third instar larval eye imaginal disc, HNT protein expression begins in the morphogenetic furrow and is refined to cells in the developing photoreceptor cell clusters just before their determination as neurons. In hnt mutant larval eye tissue, furrow markers persist abnormally posterior to the furrow, there is a delay in specification of preclusters as cells exit the furrow, there are morphological defects in the preclusters and recruitment of cells into specific R cell fates often does not occur. Additionally, genetically mosaic ommatidia with one or more hnt mutant outer photoreceptor cells, have planar polarity defects that include achirality, reversed chirality and misrotation. Mutants in the JNK pathway act as dominant suppressors of the hnt planar polarity phenotype, suggesting that HNT functions to downregulate JUN kinase (JNK) signaling during the establishment of ommatidial planar polarity. HNT expression continues in the photoreceptor cells of the pupal retina. When an ommatidium contains four or more hnt mutant photoreceptor cells, both genetically mutant and genetically wild-type photoreceptor cells fall out of the retinal epithelium, indicating a role for HNT in maintenance of epithelial integrity. In the late pupal stages, HNT regulates the morphogenesis of rhabdomeres within individual photoreceptor cells and the separation of the rhabdomeres of adjacent photoreceptor cells. Apical F-actin is depleted in hnt mutant photoreceptor cells before the observed defects in cellular morphogenesis and epithelial integrity. The analyses presented here, together with our previous studies in the embryonic amnioserosa and tracheal system, show that HNT has a general role in regulation of the F-actin-based cytoskeleton, JNK signaling, cell morphology and epithelial integrity during development.

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